[olympus]

??? Adding a point in between two other points literally can't make something more linear, it can only make it less linear.

[afthonos]

The x-axis is the planet (+aborted planet) count. You’d be shifting all later planets over by one.

[rcthompson]

I mean that the asteroid belt would be counted as a 5th planet, and Jupiter would be 6, and so on.

[olympus]

Ah, I understand now. Increasing the index of the outer planets is what would make the fit better, and the asteroid belt is a good way to justify it (and happens to be consistent with some other theories about the solar system).